“I suppose the smallness of the particles is of no consequence,” replied his father, “excepting to make it easier to heat them.”
“Why, father,” said Rollo, “I might put the end of a knitting-needle in the lamp, and I don’t see why it wouldn’t become as hot as one of the iron filings.”
“Because,” said his father, “a part of the heat would be conveyed away through the knitting-needle towards your hand, and that would keep the end which was in the flame cooler.”
“Would it, sir,” asked Rollo.
“Yes,” said his father. “The heat moves off very fast in such a case. You know, if you take a pin between your fingers, and hold the head of it in the lamp, the heat will almost immediately move along the metal, so as to heat the end that you are holding, and burn you.”
“Yes, sir,” said Rollo; “I have got burned so, very often.”
“And of course much more heat would be conveyed away when the metal was as thick as a knitting-needle.”
“Well, father,” said Rollo, “suppose a piece of the knitting-needle was broken off, and made so small that it could all be in the flame; then would it burn?”
“How could you keep it there?” asked his father.
“Why—I don’t know,” said Rollo, hesitating. “Couldn’t we contrive some way to keep it there?”